264 TRANSACTIONS OF THE [May 18, 
carbonate of lime, probably with considerable magnesia. The 
minerals, on the other hand, are chiefly silicates of lime, mag- 
nesia, iron and alumina, while there are also present titanium, 
phosphorus, boron, etc., in less amounts. The coarse calcite is 
clearly a product of recrystallization and the structure of the 
mass is totally different from that of the limestone. It is evi- 
dent that the minerals must be a product of the commingling of 
material derived from depth with the constituents of the lime- 
stone, not by fusion, but by the intervention of solutions. And 
yet, while it is impossible to avoid the conclusion that there has 
been this transfer or “ migration” of material, the phenomena are 
quite in harmony with the view that such transfer is limited in 
extent. For its effects are conspicuous only at this one point 
on the contact, and even here the action is confined to an area 
of a few yards, while, as above stated, the contact zone as a 
rule is extremely narrow. Similar facts are exhibited at many 
other points in the region. 
Nevertheless, in other cases, as will appear later, there seems 
to have been a migration of material to considerable distances, 
although even then the mineral deposits are quite clearly de- 
fined. No fixed rule appears to exist, and instances of the latter 
kind find their opposite in cases where the limestone is un- 
changed. But when the latter is true the intrusive rock itself 
is commonly modified near the contact, very often carrying a 
large amount of titanite. An example of this is shown by a 
granite a short distance south of the locality under considera- 
tion. Two probable causes for this limited change suggest them- 
selves: the purity of the limestone, and the fact that it is highly 
crystalline throughout. These two conditions require the addi- 
tion of foreign material, together with the heat, in order that any 
marked effects should result. 
The process suggested has much in common with fumarole 
action, and it can hardly be fortuitous that, together with typical 
contact minerals, there is associated the common fumarole prod- 
uct tourmaline. The same association appears elsewhere in 
the region, and, as a matter of fact, it is difficult to distinguish 
clearly between contact and fumarole action. It seems, then, 
justifiable to go a step further in tracing the genesis of the min- 
erals under consideration, and to conclude that not only are 
they contact products, but that heated solutions and gases have 
been of prime importance in their formation. 
Summarizing briefly the phenomena exhibited in this locality 
and bearing upon the problems of mineral genesis and associa- 
tion: Pyroxene, scapolite, phlogopite, mica, apatite, titanite, 
quartz, tourmaline and coarse calcite have been formed as con- 
